Simulated Photoevaporative Mass Loss From Hot Jupiters in 3d

Tripathi, Anjali; Kratter, Kaitlin M.; Murray-Clay, Ruth; Krumholz, Mark R.

doi:10.1088/0004-637x/808/2/173

Cited by 95 publications

(102 citation statements)

References 65 publications

(75 reference statements)

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“…By adopting a near-isothermal equation of state with spherical launching of the planetary wind, we do not capture the effects of asymmetric irradiation (e.g., Stone & Proga 2009;Tripathi et al 2015) which can result in nightside accretion and could affect the dynamics of the tail. Our simulations, due to their axisymmetry, also only allow for the tail to point directly away from the star and do not include stellar gravity or tidal forces.…”

Section: Summary and Discussionmentioning

confidence: 99%

Axisymmetric Simulations of Hot Jupiter–stellar Wind Hydrodynamic Interaction

Christie

Arras

2016

ApJ

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Gas giant exoplanets orbiting at close distances to the parent star are subjected to large radiation and stellar wind fluxes. In this paper, hydrodynamic simulations of the planetary upper atmosphere and its interaction with the stellar wind are carried out to understand the possible flow regimes and how they affect the Lyα transmission spectrum. Following Tremblin and Chiang, charge exchange reactions are included to explore the role of energetic atoms as compared to thermal particles. In order to understand the role of the tail as compared to the leading edge of the planetary gas, the simulations were carried out under axisymmetry, and photoionization and stellar wind electron impact ionization reactions were included to limit the extent of the neutrals away from the planet. By varying the planetary gas temperature, two regimes are found. At high temperature, a supersonic planetary wind is found, which is turned around by the stellar wind and forms a tail behind the planet. At lower temperatures, the planetary wind is shut off when the stellar wind penetrates inside where the sonic point would have been. In this regime mass is lost by viscous interaction at the boundary between planetary and stellar wind gases. Absorption by cold hydrogen atoms is large near the planetary surface, and decreases away from the planet as expected. The hot hydrogen absorption is in an annulus and typically dominated by the tail, at large impact parameter, rather than by the thin leading edge of the mixing layer near the substellar point.

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Section: Summary and Discussionmentioning

confidence: 99%

Axisymmetric Simulations of Hot Jupiter–stellar Wind Hydrodynamic Interaction

Christie

Arras

2016

ApJ

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“…Irradiation heats the atmospheres, causing them to inflate and more likely to outflow through a hydrodynamic escape mechanism. While the effects of irradiation on the mass-loss process of exoplanets have been largely studied (Lammer et al 2003; Baraffe et al 2004; E-mail: aline.vidotto@tcd.ie Lecavelier des Etangs et al 2004;Penz et al 2008;Ehrenreich & Désert 2011;Yelle 2004;Tian et al 2005;Garcia Munoz 2007;Murray-Clay et al 2009), and several works have studied how stellar winds interact with escaping atmospheres (Schneiter et al 2007;Khodachenko et al 2012Khodachenko et al , 2015Shaikhislamov et al 2014;Villarreal D'Angelo et al 2014Tripathi et al 2015;Carroll-Nellenback et al 2017;Vidotto et al 2018;Debrecht et al 2019;Daley-Yates & Stevens 2019;Esquivel et al 2019;McCann et al 2019), the effects of stellar ejecta in confining the escape of exoplanetary atmospheres have been less explored. This is the subject of the present paper.…”

Section: Introductionmentioning

confidence: 99%

Stellar wind effects on the atmospheres of close-in giants: a possible reduction in escape instead of increased erosion

Vidotto

Cleary

2020

Monthly Notices of the Royal Astronomical Society

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The atmospheres of highly irradiated exoplanets are observed to undergo hydrodynamic escape. However, due to strong pressures, stellar winds can confine planetary atmospheres, reducing their escape. Here, we investigate under which conditions atmospheric escape of close-in giants could be confined by the large pressure of their host star's winds. For that, we simulate escape in planets at a range of orbital distances ([0.04, 0.14] au), planetary gravities ([36%, 87%] of Jupiter's gravity), and ages ([1, 6.9] Gyr). For each of these simulations, we calculate the ram pressure of these escaping atmospheres and compare them to the expected stellar wind external pressure to determine whether a given atmosphere is confined or not. We show that, although younger close-in giants should experience higher levels of atmospheric escape, due to higher stellar irradiation, stellar winds are also stronger at young ages, potentially reducing escape of young exoplanets. Regardless of the age, we also find that there is always a region in our parameter space where atmospheric escape is confined, preferably occurring at higher planetary gravities and orbital distances. We investigate confinement of some known exoplanets and find that the atmosphere of several of them, including π Men c, should be confined by the winds of their host stars, thus potentially preventing escape in highly irradiated planets. Thus, the lack of hydrogen escape recently reported for π Men c could be caused by the stellar wind.

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“…The multi-fluid aeronomic code of the model includes the hydrogen plasma photo-chemistry, the self-consistent stellar radiation energy input to the upper atmosphere of the planet that drives its expansion, and the effects of stellar and planetary gravity, as well as the SW plasma flow. The HD/MHD modeling of hot close-orbit exoplanets has been steadily progressing nowadays from 1D to 3D codes (Bisikalo et al 2013, Tremblin and Chiang 2013, Trammell et al 2014Owen et al 2014, Khodachenko et al 2015, Matsakos et al 2015, Tripathi et al 2015, Shaikhislamov et al 2016, 2018a,b, Erkaev et al 2017. At the same time, the majority of existing 3D models have not yet reached the same level of physics-and-chemistry complexity as that of the first generation of 1D aeronomy models, which would allow self-consistent simulation of the outflowing PW and its interaction with the surrounding SW.…”

Section: Introductionmentioning

confidence: 99%

Global 3D Hydrodynamic Modeling of In-transit Lyα Absorption of GJ 436b

Khodachenko

Шайхисламов

Lämmer

et al. 2019

ApJ

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Using a global 3D, fully self-consistent, multi-fluid hydrodynamic model, we simulate the escaping upper atmosphere of the warm Neptune GJ436b, driven by the stellar XUV radiation impact and gravitational forces and interacting with the stellar wind. Under the typical parameters of XUV flux and stellar wind plasma expected for GJ436, we calculate in-transit absorption in Lyα and find that it is produced mostly by Energetic Neutral Atoms outside of the planetary Roche lobe, due to the resonant thermal line broadening. At the same time, the influence of radiation pressure has been shown to be insignificant. The modelled absorption is in good agreement with the observations and reveals such features as strong asymmetry between blue and red wings of the absorbed Lyα line profile, deep transit depth in the high velocity blue part of the line reaching more than 70%, and the timing of early ingress. On the other hand, the model produces significantly deeper and longer egress than in observations, indicating that there might be other processes and factors, still not accounted, that affect the interaction between the planetary escaping material and the stellar wind. At the same time, it is possible that the observational data, collected in different measurement campaigns, are affected by strong variations of the stellar wind parameters between the visits, and therefore, they cannot be reproduced altogether with the single set of model parameters.Keywords: hydrodynamicsplasmasplanets and satellites: individual: exoplanetsplanets and satellites: physical evolutionplanets and satellites: atmosphereplanet-star interactions 2004, García Muñoz 2007, Koskinen et al. 2007) clarified the basic physics of the escaping upper atmosphere in the form of planetary wind (further PW), which includes the XUV heating, hydrogen plasma photo-chemistry, radiation cooling, gravitational and thermal pressure forces. They helped to explain some of the in-transit spectral observations by the presence of an expanded partially ionized upper atmospheres, which fill the Roche lobes of hot giant exoplanets, such as HD209458b and HD189733b (Ben-Jaffel 2007, Ben-Jaffel & Sona Hosseini 2010, Koskinen et al. 2007. These expanding atmospheres were shown to be sufficiently dense to produce the absorption in Lyα due to natural line broadening mechanism.However, the detection of absorption in the resonant lines of heavy elements such as OI, CII, and SiIII , Linsky et al. 2010, has shown that the absorbing material of planetary origin far beyond the Roche lobe has to be considered as well (Ben-Jaffel & Sona Hosseini 2010, Shaikhislamov et al. 2018a. The presence of a huge hydrogen corona also is a prerequisite for the explanation of strong in-transit Lyα absorption of GJ436b. By this, there is another crucial factor, besides of the Roche lobe effect, which has to be properly taken into account in the modeling of large-scale plasma dynamics around the close-orbit exoplanetsthe stellar wind (further SW) plasma. Self-consistent description of the escaping multi-co...

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Simulated Photoevaporative Mass Loss From Hot Jupiters in 3d

Cited by 95 publications

References 65 publications

Axisymmetric Simulations of Hot Jupiter–stellar Wind Hydrodynamic Interaction

Axisymmetric Simulations of Hot Jupiter–stellar Wind Hydrodynamic Interaction

Stellar wind effects on the atmospheres of close-in giants: a possible reduction in escape instead of increased erosion

Global 3D Hydrodynamic Modeling of In-transit Lyα Absorption of GJ 436b

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